The makers of Taser electric stun guns say their claims of safety are backed by more than 100,000 police officers who have been shocked during training sessions without suffering a single serious injury.

But a doctor working for Taser says a one-second burst from the stun gun was responsible for fracturing the back of a Maricopa County sheriff's deputy in 2002.

The doctor, in a memo obtained by The Arizona Republic , tells Taser that he evaluated former Deputy Samuel Powers and found the officer "sustained a T7 compression fracture as the result of the Taser incident."

Powers was the first person to file a product liability lawsuit against Scottsdale's Taser International, claiming that the shock during a mandatory training exercise forced him into medical retirement and has left him suffering permanent injuries.

He has been joined by other police officers around the country who are coming forward with lawsuits and complaints about injuries they attribute to being shocked with a Taser.

The injury reports appear to contradict Taser's principal assertion of safety and may undercut one of the company's most effective sales pitches. The doctor's memo surprises and concerns police training instructors from Miami to Portland who have shocked their own officers during training and say this could lead them to re-examine how Tasers are used.

The memo also raises questions about Taser's reports to its shareholders. In repeated filings to the Securities and Exchange Commission, Taser says that Powers is alleging that he "injured his shoulder" and makes no mention of the fracture.In his memo, Phoenix orthopedic surgeon Stephen Brown says an undiagnosed case of osteoporosis, a bone-weakening disease, left Powers vulnerable to the Taser shock.

"I think this patient had evidence for pre-existing osteoporosis, which is why, when he received the electrical impulse and resultant muscle contraction, he sustained a T7 compression fracture," the doctor says.

Brown's conclusion that osteoporosis contributed to Powers' injury may add to the list of health conditions that have been cited in several injuries and deaths following shocks from the 50,000-volt stun gun. Among those are heart conditions, mental delirium and drug intoxication.

Although medical examiners nationwide have linked Taser to 11 deaths, company officials claim the stun gun was not a factor and the people would have died whether or not they were shocked.

With Tasers being used by about 5,500 law enforcement agencies, including officers assigned to high school and college campuses, the question of safety is expanding.

Taser officials did not respond to multiple requests for interviews last week.

Police 'brainwashed'

Phoenix lawyers John Dillingham and Tom Wilmer, who represent Powers, say law enforcement agencies have been bombarded by safety assurances from Taser and are buying thousands of stun guns in the belief they have never caused an injury or death.

"This is not a problem with law enforcement. It's a problem with Taser," Dillingham says. "Police officers are brainwashed into thinking that the (stun) gun is safe. They are brainwashed into taking a hit during training and then to use it in the field anytime they want."

Powers, a 15-year veteran of the Maricopa County Sheriff's Office, says in his lawsuit that he was repeatedly told the stun did not pose any risks before he was shocked during a mandatory Taser certification training session.

A video that recorded the training shows Powers standing between two officers, who were supposed to keep him from falling down.

Electrodes are attached to his left ankle and right shoulder. The shock, which lasts no more than a second, causes Powers to yell in pain as his body contracts.

"Immediately upon being shocked, Powers suffered severe pain in his back. He could hardly breath," his lawsuit states. "Within minutes, he realized he had sustained (a) severe injury. He subsequently learned that the shock had caused his seventh thoracic vertebrae to be crushed."

Powers' suit was filed in February in Maricopa County Superior Court. It is scheduled to go to trial in June.

Taser lawyers say Powers should have refused to be shocked. They say he had previously been treated for two herniated disks and had been warned about the muscle contractions caused by Taser.

And before being shocked, lawyers say, Powers watched 12 other deputies experience the shock.

"He observed each deputy's body stiffen from involuntary muscle contractions caused by the Taser, fall to the ground in many instances, and scream out in pain," lawyers say in court filings. "Appreciating the risk and its magnitude, he nevertheless chose to assume that risk by receiving a sample exposure of the Taser."

To help its defense of Powers' suit, Taser lawyers hired Brown to perform an "independent medical examination" in September.

In his memo, Brown says he reviewed Powers' medical records dating back to 1997. He says X-rays taken of Powers several months before the Taser incident do not show any damage to the spine. X-rays taken after the incident confirmed the fracture resulted in a 50 percent reduction of one of the bones in the spinal column.

Brown's office says Taser lawyers have advised him not to comment on the case.

According to Internet medical directories, Brown has practiced in Arizona since 1979 and specializes in joint reconstructive surgery and treating sports-related injuries.

He received his medical degree from Johns Hopkins University School of Medicine in 1973 and began his orthopedic surgical training at Harvard.

Brown notes that Powers, now 46, has moved to Ohio and works as a field appraiser, inspecting and measuring building sites.

"I certainly do feel that (Powers) is not capable of being a police officer if it puts him at risk with very physical activities," Brown says in his memo. "However, I feel the primary reason why he cannot do this is because of his ongoing osteoporosis."

Brown says the compression fracture has healed and is unlikely to give Powers further problems.

"But given the nature of his osteoporosis, he runs the risk of further compression fractures with physical events," he says.

Even after Brown's memo outlined Powers' injuries, Taser continued reporting to shareholders that his lawsuit alleged a shoulder injury.

"We believe the plaintiff's claims are without merit and that this litigation will have no material adverse effect on our business," Taser said in a November report to the Securities and Exchange Commission.

Publicly traded companies are required to file quarterly reports so investors can evaluate the financial health and potential risks facing a company.

"As a regulator, I'm concerned when the public statements investors are relying on are misstated," says Marc Spitzer, chairman of the Arizona Corporation Commission, which regulates public utilities and corporations.

Shocks drive sales

Video images of police being shocked have become commonplace on television newscasts across the country. Taser encourages police officers, along with its employees, shareholders and members of the media to experience a sample shock from the stun gun.

In dozens of press releases and media interviews, the company has touted those shocks as evidence that the stun gun works.

"The field test is really what drives the sales," Taser Chief Executive Officer Rick Smith told The Republic in an interview this year. "That and the volunteering. When officers volunteer to be hit with it . . . they see and feel how effective it is, that is generally when we see it convert to sales."

In his suit, Powers claims Taser "implemented a marketing plan based on misinformation, overstatements, inaccuracies, half truths and false statements in an effort to bolster its claim that 'hits' from Taser weapons do not cause death or permanent injuries."

Taser International in the past required officers to experience an abbreviated shock before being allowed to carry the stun gun. In 2000, Taser policy shifted to a "strong recommendation" that students take a sample hit from the stun gun.

Taser's CEO says the shock helps officers to understand the power and potential of the weapon.

"We used to require it, but then we made a change," Smith said previously, explaining that various police unions worried about shocks becoming a condition of employment.

"From the company's perspective, it is important because (a shock) gets rid of the skepticism," he says. "From the agency's perspective, it is very important so that (officers) can articulate what they are doing to somebody else."

But only a day after Powers filed his suit in February, Taser blamed the Sheriff's Office for "unreasonably requiring" officers to be shocked.

"If there is evidence that the shock from the (Taser) caused any injuries or damages to the plaintiff," Taser lawyers said in a Feb. 24 court filing, "(Maricopa County Sheriff's Office) and/or Sheriff Joe Arpaio are at fault for unreasonably requiring the plaintiff to be shocked by the Taser . . . as part of its non-lethal weapons training."

A judge tossed out Taser's request to redirect the suit at the Sheriff's Office.

"It looks like a double standard," Arpaio said in an interview. "They are pushing this on me because we used their equipment."

At the time Powers was shocked, Arpaio says his office was following Taser's recommendation and required officers to be hit with a Taser. He says it is no longer a requirement, but an option.

Arpaio knew that Powers had been injured and filed suit against Taser. He says he has bought hundreds of the guns based on the company's claim that it has not caused a death or injury.

Arpaio was unaware of the memo from Taser's doctor until being contacted by a reporter. He says it will prompt him to call for an internal study of Taser safety.

"I'm going to look at the history of Tasers. I'll assign staff to do it," Arpaio says, adding that risks were easily overlooked until an officer got hurt.

The Phoenix Police Department, the first major metropolitan police department in the country to issue Tasers to all of its officers, strongly recommended that officers experience Taser shocks until 2002. That's when two officers suffered minor injuries.

Sgt. Randy Force, department spokesman, says one officer dislocated his shoulder and the other chipped a tooth, both from falls after being shocked.

Force, who says the Taser is one of the best tools law enforcement officers have at their disposal, points out that officers suffer injuries in all types of exercises. That includes firearms training, where officers have inadvertently shot themselves.

The department now prohibits officers from being shocked.

"We stopped doing it because we were putting people at risk," Force says. "It's one thing to be injured when you don't have an option. But we felt that we did have many options."

Safety issues expanded

Safety issues related to police training add to the concerns raised by other injuries and deaths following Taser shocks.

For years, Taser maintained that its stun guns never caused a death or serious injury. As proof, Taser officials said no medical examiner had ever cited the gun in an autopsy report.

But a Republic investigation this summer found that Taser never had the autopsy reports and didn't start collecting them until April.

Using computer searches, autopsy reports, police reports, media reports and Taser's own records, the newspaper has identified 84 deaths following police Taser strikes in the United States and Canada since 1999.

Of those, 11 autopsy reports to date have linked deaths to the stun gun. Medical examiners cited Taser as a cause or contributing factor in eight deaths and could not rule it out as a cause in three others.

Taser officials say the stun gun has saved thousands of lives, giving police the most technologically advanced weapon in decades. Officers agree and credit Tasers with reducing police shootings and injuries to suspects.

Even officers who claim to be injured by the stun gun don't dispute Taser's track record. But they say the company has glossed over potential problems.

"I am really appalled at how departments around the world are taking Taser blindly at their word that the (Taser) is safe, with only the scant testing done," says C. Samuel Babin, a Louisiana sheriff's deputy who is on medical leave with a condition he believes is Taser related.

"I couldn't imagine the (stun gun) passing the scrutiny of an FDA application if Taser was a drug company trying to get a new drug on the market."

Although Tasers were initially marketed as an alternative to deadly force, the stun guns have replaced batons, chemical spray and physical restraint as the weapon of choice for stopping suspects.

Police often use Tasers as a compliance tool against people who make threatening gestures, try to run away or don't obey commands.

A Taser looks and operates like a gun, except that it fires two steel barbs up to 21 feet. The barbs are attached to wires that deliver 5-second bursts of electricity.

Powers received only a fraction of the shock that most suspects experience on the street. He was shocked for one second while criminal suspects often receive multiple shocks lasting five seconds each.

Officers can re-cycle the gun and deliver repeated shocks by holding down the trigger. The cartridge housing the barbs can also be removed, allowing the gun to be used in a fashion similar to a cattle prod, which officers call a "drive-stun."

In Phoenix last year, almost half of the 377 people shot by police with a Taser were shocked more than once.

Despite Taser's repeated claim that no officer has been injured, the company's November report to the Securities and Exchange Commission outlines three additional lawsuits alleging injuries during Taser training.

Those alleged injuries include a muscle and nerve injury; an arm and shoulder injury; and a rotator cuff injury.

Taser follows the description of each lawsuit with a line saying the case is without merit and has been turned over to the company's insurance carrier.

"Powers' injury is not an isolated event," Dillingham says. "If you look into it nationwide, you will find ruptured disks, other fractures and injuries to other joints."

Babin, a 17-year law enforcement veteran in Slidell, La., says he heard from a dozen police officers after posting a message on a police magazine Web site asking officers about injuries.

"The most common injuries . . . were dislocations or spinal fractures, which would be consistent with the extreme jolt you experience," he says.

Babin says he wanted to hear from other officers after finding his arms and legs covered in bruises following a Taser shock in May.

Babin says another officer who attended his May 4 Taser training class suffered severe chest pains. He says doctors told the officer "the extreme shock began eating away skin tissue from the area around a previous surgery."

Babin says he still bears the scar of a Taser burn. After being shocked, he says, he developed an autoimmune condition that left his body attacking blood platelets. He says he was diagnosed with bone marrow disease that causes spontaneous bleeding and that doctors have been unable to rule out Taser as a cause.

"I really believe officers need to be made aware of the potential danger before subjecting (themselves) to the training," he says.

"Regardless of whether the training is mandatory, as in my case, no one cannot possibly make a voluntary and informed decision if Taser continues to stonewall the issue and the dangers go unheard."

Babin says the instructor and another police administrator "insisted the experience was safe."

Still, Babin doesn't dispute the benefits of Taser.

"There has been one consensus amongst all of us in law enforcement. All agree, despite injuries . . . that the Taser is a great tool," he says. "I think the current media attention has failed to consider that any force used by police could be and will be life-threatening."

Memo shocks trainers

But police training officers say they were not told about any significant officer injuries. None contacted about Powers' case were familiar with it. And they expressed concern over Brown's evaluation.

"I'm in disbelief," says Miami Police Sgt. Richard Gentry. "That's the first time I've heard anything like that. I will definitely be keeping my eyes open for that."

While it isn't required, Gentry says the department highly recommends officers experience the shock of a Taser.

"I have rode the five seconds twice, myself," he says. "We try to make training as real as possible."

Gentry credits the Taser as one of the most effective weapons ever. He believes that it is responsible for reducing police shootings and preventing officers from engaging in violent confrontations. He says the stun gun was used 250 times between January and November of this year, far more than any other type of force.

Gentry can't recall any officer being injured during Taser training. He says Brown's memo raises issues about pre-existing conditions and hidden problems. He says every officer goes through a physical exam as part of the hiring process, but that does not include tests for diseases such as osteoporosis.

"There is no question that if there is factual data out there, then it should be part of the discussion," he says, adding that he wants to know everything he can about any weapon his department asks officers to carry. "(Officers) are relying on us."

In Portland, Ore., where the department is set to issue Tasers to every officer, Sgt. Robert Day says the memo raises concerns.

"That's the first I've heard about," says Day, who spent months researching Tasers prior to the department's decision to buy the stun guns. "We have certainly not experienced anything like that."

He says until recently, every Taser operator has taken a shock, but as the department expands Taser use, about 30 percent of officers have opted out of the experience. He says Portland officers have not reported any medical problems.

Like Miami and other departments, Portland officers are required to go through a basic physical exam before being hired.

"I would really like more information on it," he says.

More at risk

Brown's evaluation raises the question about Taser's impact on people with osteoporosis and the possibility that many more people could be injured if shocked with a Taser.

The United States Surgeon General advises that osteoporosis affects one in two women and one in four men over age 50.

Osteoporosis is often thought of as a bone-weakening disease. It deteriorates bone tissue, leaving people at risk for fractures.

The National Osteoporosis Foundation in Washington D.C., estimates that 44 million Americans, or roughly 55 percent of all adults over the age of 50, have the disease.

"While osteoporosis is often thought of as an older person's disease, it can strike at any age," the non-profit foundation says on its Web site. "Osteoporosis is responsible for more than 1.5 million fractures annually."

The problem is most people don't know they have the disease until it is too late.

"Osteoporosis is often called the silent disease because bone loss occurs without symptoms," the foundation reports. "People may not know that they have osteoporosis until their bones become so weak that a sudden strain, bump or fall causes a fracture or a vertebra to collapse."

Brown notes in his memo that Powers was unaware that he had the disease until he underwent a bone density test in September 2002. The test was ordered by a doctor trying to treat the fracture following the Taser shock.

Portland police trainer Day says concerns about osteoporosis could reinvigorate the issues over Taser safety in general. He says those issues need to be weighed against the stun gun's benefits, which he believes are many.

He says he doesn't know if it will change the way Tasers are used, but there needs to be a full disclosure.

"I'm not just talking about officers. I'm thinking about citizens," he says. "There is obviously a risk there."